You know what would be a GREAT idea?
If you have a one-day, one-park pass, they should let you go to another park during, say, the last hour or two of the day. It would give you a taste of that park and maybe make you want to go back the next day. Plus, if you're spending the day in MK, you would still be able to go see Fantasmic or one of the other nighttime shows. Given how much repeat-business Disney gets, it might very likely convince people to, on their next trip, get the park hoppers!